DATA SHEET AAT2550 Total Power Solution for Portable Applications General Description Features The AAT2550 is a fully integrated total power solution Two Step-Down Converters: with two step-down converters plus a single-cell lithium- 600mA Output Current per Converter ion / polymer battery charger. The step-down converter V Range: 2.7V to 5.5V IN input voltage range spans 2.7V to 5.5V, making the 1.4MHz Switching Frequency AAT2550 ideal for systems powered by single-cell lithi- Low R 0.4 Integrated Power Switches DS(ON) um-ion/polymer batteries. Internal Soft Start 27A Quiescent Current per Converter The battery charger is a complete constant current/ con- Highly Integrated Battery Charger: stant voltage linear charger. It offers an integrated pass Programmable Charging Current from 100mA to 1A device, reverse blocking protection, high current accu- Pass Device racy and voltage regulation, charge status, and charge Reverse Blocking Diodes termination. The charging current is programmable via Current Sensing Resistor external resistor from 100mA to 1A. In addition to these Digital Thermal Regulation standard features, the device offers over-voltage, over- Short-Circuit, Over-Temperature, and Current Limit current, and thermal protection. Protection The two step-down converters are highly integrated, QFN44-24 Package operating at a switching frequency of 1.4MHz, minimiz- -40C to +85C Temperature Range ing the size of external components while keeping switching losses low. Each converter has independent Applications input, enable, and feedback pins. The output voltage ranges from 0.6V to V . Each converter is capable of Cellular Telephones IN delivering up to 600mA of load current. Digital Cameras Handheld Instruments The AAT2550 is available in a Pb-free, space-saving, MP3, Portable Music, and Portable Media Players thermally-enhanced QFN44-24 package and is rated PDAs and Handheld Computers over the -40C to +85C temperature range. Typical Application Battery Pack Adapter ADP BAT Batt+ AAT2550 TS STAT1 STAT2 Batt- CT Serial Interface DATA ADPSET R SET Temp V LXA OUTA ENBAT C OUTA INA FBA Li-Ion Battery or Adapter INB V LXB OUTB C ENA OUTB FBB ENB GND Skyworks Solutions, Inc. Phone 781 376-3000 Fax 781 376-3100 sales skyworksinc.com www.skyworksinc.com 1 202174B Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. March 19, 2013 19 12 ENB ENBAT 20 11 INB AGND 21 10 FBB AGND 22 9 AGND ADP 23 8 FBA BAT 24 7 INA N/C DATA SHEET AAT2550 Total Power Solution for Portable Applications Pin Descriptions Pin Symbol Function Enable pin for Converter A. When connected to logic low, it disables the step-down converter and con- 1 ENA sumes less than 1A of current. When connected to logic high, the converter operates normally. Power switching node for Converter A. Connect the inductor to this pin. Internally, it is connected to the 2 LXA drain of both high- and low-side MOSFETs. Power ground. Connect the PGND pins together as close to the IC as possible. Connect AGND to PGND at a 3, 17 PGND single point as close to the IC as possible. 4 DATA Status report to the microcontroller via serial interface (open drain). 5, 7 N/C Not connected. Charge current set point. Connect a resistor from this pin to ground. Refer to Typical Characteristics curves 6 ADPSET for resistor selection. 8 BAT Battery charging and sensing. Connect the positive terminal of the battery to BAT. 9 ADP Input for adapter charger. 10, 11, 22 AGND Analog signal ground. Connect AGND to PGND at a single point as close to the IC as possible. Enable pin for the battery charger. When connected to logic low, the battery charger is disabled and con- 12 ENBAT sumes less than 1A of current. When connected to logic high, the charger operates normally. 13 TS Temperature sense input. Connect to a 10k NTC thermistor. 14 STAT2 Battery charge status indicator pin to drive an LED. It is an open drain input. 15 STAT1 Battery charge status indicator pin to drive an LED. It is an open drain input. Timing capacitor to adjust internal watchdog timer. Sets maximum charge time for adapter powered 16 CT trickle, constant current, and constant voltage charge modes. Power switching node for Converter B. Connect the inductor to this pin. Internally, it is connected to the 18 LXB drain of both high- and low-side MOSFETs. Enable pin for Converter B. When connected to logic low, it disables the step-down converter and con- 19 ENB sumes less than 1A of current. When connected to logic high, the converter operates normally. 20 INB Input voltage for Converter B. Output voltage feedback input for Converter B. FBB senses the output voltage B for regulation control. The 21 FBB FBB regulation threshold is 0.6V. A resistive voltage divider is connected to the output B, FBB, and AGND. Output voltage feedback input for Converter A. FBA senses the output voltage A for regulation control. The 23 FBA FBA regulation threshold is 0.6V. A resistive voltage divider is connected to the output A, FBA, and AGND. 24 INA Input voltage for Converter A. EP Exposed paddle connect to ground directly beneath the package. Pin Configuration QFN44-24 (Top View) 1 18 ENA LXB 2 17 LXA PGND 3 16 PGND CT 4 15 DATA STAT1 5 14 N/C STAT2 6 13 TS ADPSET Skyworks Solutions, Inc. Phone 781 376-3000 Fax 781 376-3100 sales skyworksinc.com www.skyworksinc.com 2 202174B Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice. March 19, 2013